diff --git a/graph/prim.cpp b/graph/prim.cpp
index 5cc70bd39..0432926ef 100644
--- a/graph/prim.cpp
+++ b/graph/prim.cpp
@@ -3,56 +3,55 @@
 #include <queue>
 #include <vector>
 
-const int MAX = 1e4 + 5;
-typedef std::pair<int, int> PII;
+using PII = std::pair<int, int>;
 
-bool marked[MAX];
-std::vector<PII> adj[MAX];
-
-int prim(int x) {
+int prim(int x, const std::vector< std::vector<PII> > &graph) {
     // priority queue to maintain edges with respect to weights
     std::priority_queue<PII, std::vector<PII>, std::greater<PII> > Q;
-    int y;
-    int minimumCost = 0;
-    PII p;
+    std::vector<bool> marked(graph.size(), false);
+    int minimum_cost = 0;
 
     Q.push(std::make_pair(0, x));
     while (!Q.empty()) {
         // Select the edge with minimum weight
-        p = Q.top();
+        PII p = Q.top();
         Q.pop();
         x = p.second;
         // Checking for cycle
-        if (marked[x] == true)
+        if (marked[x] == true) {
             continue;
-        minimumCost += p.first;
+        }
+        minimum_cost += p.first;
         marked[x] = true;
-        for (int i = 0; i < adj[x].size(); ++i) {
-            y = adj[x][i].second;
-            if (marked[y] == false)
-                Q.push(adj[x][i]);
+        for (const PII &neighbor : graph[x]) {
+            int y = neighbor.second;
+            if (marked[y] == false) {
+                Q.push(neighbor);
+            }
         }
     }
-    return minimumCost;
+    return minimum_cost;
 }
 
 int main() {
-    int nodes, edges, x, y;
-    int weight, minimumCost;
-
+    int nodes = 0, edges = 0;
     std::cin >> nodes >> edges;  // number of nodes & edges in graph
-    if (nodes == 0 || edges == 0)
+    if (nodes == 0 || edges == 0) {
         return 0;
+    }
+
+    std::vector< std::vector<PII> > graph(nodes);
 
     // Edges with their nodes & weight
     for (int i = 0; i < edges; ++i) {
+        int x = 0, y = 0, weight = 0;
         std::cin >> x >> y >> weight;
-        adj[x].push_back(std::make_pair(weight, y));
-        adj[y].push_back(std::make_pair(weight, x));
+        graph[x].push_back(std::make_pair(weight, y));
+        graph[y].push_back(std::make_pair(weight, x));
     }
 
     // Selecting 1 as the starting node
-    minimumCost = prim(1);
-    std::cout << minimumCost << std::endl;
+    int minimum_cost = prim(1, graph);
+    std::cout << minimum_cost << std::endl;
     return 0;
 }